Table 1.

Steady-state kinetic parameters for M. smegmatis MC² 155 APK variants

Reactions were assayed in 20 mm Tris, pH 8, and 150 mm NaCl at 25 °C. Errors for kinetic parameters are the standard deviation determined from nonlinear regression fitting of kinetic data as described in materials and methods. Nonlinear regression fittings had R² values greater than 0.99.

	kcat	Km	kcat/Km
	s−1	mm	m−1 s−1
APKMSM0270 WT
(S)-1-amino-2-propanol	8.7 ± 0.05	0.373 ± 0.006	2.3 × 104
(R)-1-amino-2-propanol	3.2 ± 0.2	1.54 ± 0.15	2.1 × 103
(R/S)-1-amino-2-butanol	8.8 ± 0.2	1.11 ± 0.066	7.9 × 103
Ethanolaminea	8.1 ± 0.5	193 ± 13	4.2 × 101
ATP	8.0 ± 0.2	0.27 ± 0.02	3.0 × 104
APKMSM0270 variantsb
E33Aa	0.068 ± 0.003	26 ± 2	2.6
R290Aa	0.44 ± 0.07	72 ± 15	6.1
D235A	NAc	NA	NA
R213A	0.85 ± 0.01	2 ± 0.1	4.3 × 102
APKMSM0780 Δ1–23
S-(+)-1-Amino-2-propanol	4.35 ± 0.03	0.069 ± 0.003	6.3 × 104
ATP	2.79 ± 0.02	0.074 ± 0.004	3.8 × 104

^a Kinetic parameters are calculated by extrapolation from collected data due to inability to reach substrate saturation under assay conditions.

^b Variant kinetic parameters are for S-(+)-1-amino-2-propanol with saturating concentrations of ATP.

^c NA, not applicable.